Thanks for the feedback! I actually think your comment helped me get an idea of why they stick. It's probably the difference between move_and_slide and move_and_collide. I'll have to do some more reading and experimentation with those two.
I came across this in my own game as well. I think I solved it with setting the CharacterBody's motion mode to floating instead of grounded (according to the editor's note it changes the behavior of move_and_slide). I used 4.0 RC 1 and my game is 2D so the solution in 3D might not be the same.
